Recently, researches into AR (Argumented Reality) technologies in which information of a virtual space is superimposed on a real space to output resultant information gain popularity. For information presenting apparatuses based on AR technologies typically include a head-mounted output apparatus of a video see-through type equipped with a camera and a portable terminal. Use of these terminals allows information (a virtual object) to be superimposed on a video in a real space taken by the camera and the user to feel as if the virtual object were present in the real space.
For example, patent document 1 proposes that information is registered with a specific card and this card is recognized with a terminal camera, thereby superimposing the information (a virtual object) on the location where the card exists.
In addition, it is also proposed that information is added to a location identified by positional information obtained from GPS (Global Positioning System) and the added information is presented to a user who visits that location. Further, a system is proposed in which, in addition to positional information, information to be presented is changed in accordance with the orientation of a user by use of an electronic compass.